Drilling affirms high-grade Porter silver
Last updated 6/13/2019 at 3:55pm
StrikePoint Gold Inc. Jan. 9 reported that a 25-hole drill program at Porter has cut high-grade silver mineralization within and beyond the historical resource area on this past producing property just outside of Stewart, British Columbia.
Located on Mount Rainey, which overlooks Stewart from the south, the Porter property hosts historic silver mines that date back to the dawn of the 20th Century.
The majority of the past production on Porter comes from the Prosperity-Porter Idaho veins on the south side of Mount Rainey. Roughly 27,123 metric tons of ore averaging 2,542 grams (73.8 ounces) per metric ton silver and 1 g/t gold was mined from this vein system between 1929 and 1931, producing roughly 2.2 million oz of silver. This high-grade silver ore was shipped to the port at Stewart via aerial tramway.
StrikePoint believes the ore mined from Prosperity-Porter Idaho and Silverado, a smaller high-grade silver mine that overlooks Stewart from the north side of Mount Rainey, could represent opposite ends of a larger mineralized system. Recent glacial retreat has exposed the ground between these past producing mine sites, providing StrikePoint the opportunity to explore for a connection between the deposits.
According to a resource estimate prepared in 2012, the Porter side of Mount Rainey hosts 394,700 metric tons of indicated resource averaging 868 g/t silver (11 million ounces) silver, 3.37 percent lead and 1.41 percent zinc; and 88,900 metric tons of inferred resources grading 595 g/t (1.7 million oz) silver.
This historical resource does not include the Silverado veins.
This 4,304-meters diamond drill program carried out by StrikePoint in 2018 included 22 holes targeting Porter and three at Silverado.
• Hole PIP18-010, drilled within the historical Prosperity-Porter Idaho resource area, cut five meters averaging 819 grams per metric ton silver along the D-Vein.
• PIP18-009, which also targeted D-Vein, cut 2.5 meters of 184 g/t silver from 53 meters and 0.5 meters of 146 g/t gold from 63 meters.
• PIP18-012, which targeted the Blind Vein and is outside the historical resource area, cut one meter of 2,241 g/t silver.
• PIP18-014, also targeting the Blind Vein, cut two meters averaging 637 g/t silver, including 0.5 meters of 2,506 g/t silver. Strikepoint said this intercept appears to represent a previously untested lower continuation of the D-Vein.
The company says the seven holes that intercepted the Blind Vein last year are significant as this structure, which lies between D- and Prosperity veins, was not included in the 2012 resource calculation.
Drilling at Wake and Angelo, two other historically recognized veins at Porter, cut less coherent, localized pockets of mineralization along a general trend. Such styles of mineralization are also noted along the major veins at Porter, so it is possible that richer sections remain at depth and are yet to be drilled.
Drilling at Silverado affirms extension of the discrete vein systems although the grades were lower than anticipated.
One hole drilled at Silverado, SIL18-001, cut 1.5 meters of 154 g/t silver. Another, SIL18-002 cut four meters of 53 g/t silver.
Overall, the results from the 2018 drill program reinforce the grades in the 2012 resource calculation, lending confidence to the historical resource, and demonstrates high-grade silver ore remains in the ground despite the historic mining at Porter.
The nature of the Porter-Silverado system seems to show veins pinching and swelling with grades fluctuating along them, so mineralization of any level along the structure is very encouraging. Intercepts at Silverado are also stepped back around 150 meters from the furthest extents of the old workings, and so does show some continuity that could connect the Porter and Silverado systems.
StrikePoint also said the data collected from the 2018 drilling and surface mapping, coupled with decades of historical information, indicate that the original concept of five steeping dipping veins is oversimplified, and that several other geological mechanisms are at play that also form trap sites for mineralization.
Perhaps the most interesting concept currently is that the main D-Vein is part of a synclinal bowl-shaped fold that encapsulates the Blind and Prosperity veins. StrikePoint says such a structure would account for unexplained veins encountered during historical mining, as well as the Flat Vein-Honest John Vein it discovered last year to the west of the historic Porter system. This model also places the more disseminated Wake and Angelo veins on the outside of this structure and could explain the variation seen in structure and mineralogy.
The concept of mineralized bowl-shaped features is not unprecedented in the area, with Ascot Resource Ltd.'s nearby Premier Mine having a similar shaped structure hosting their main high-grade gold targets.
StrikePoint said work on the geological model is ongoing and is subject to change as more information is added to the dataset.